lkml.org 
[lkml]   [2013]   [Jul]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v6 7/8] Documentation:cpufreq:boost: Update BOOST documentation
    Date
    Since the support for software and hardware controlled boosting has been
    added, the corresponding Documentation entry had been updated.

    Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
    Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>

    ---
    Changes for v6:
    - None

    Changes for v5:
    - New patch

    Documentation/cpu-freq/boost.txt | 26 +++++++++++++-------------
    1 file changed, 13 insertions(+), 13 deletions(-)

    diff --git a/Documentation/cpu-freq/boost.txt b/Documentation/cpu-freq/boost.txt
    index 9b4edfc..dd62e13 100644
    --- a/Documentation/cpu-freq/boost.txt
    +++ b/Documentation/cpu-freq/boost.txt
    @@ -17,8 +17,8 @@ Introduction
    Some CPUs support a functionality to raise the operating frequency of
    some cores in a multi-core package if certain conditions apply, mostly
    if the whole chip is not fully utilized and below it's intended thermal
    -budget. This is done without operating system control by a combination
    -of hardware and firmware.
    +budget. The decision about boost disable/enable is made either at hardware
    +(e.g. x86) or software (e.g ARM).
    On Intel CPUs this is called "Turbo Boost", AMD calls it "Turbo-Core",
    in technical documentation "Core performance boost". In Linux we use
    the term "boost" for convenience.
    @@ -48,24 +48,24 @@ be desirable:
    User controlled switch
    ----------------------

    -To allow the user to toggle the boosting functionality, the acpi-cpufreq
    -driver exports a sysfs knob to disable it. There is a file:
    +To allow the user to toggle the boosting functionality, the cpufreq core
    +driver exports a sysfs knob to enable or disable it. There is a file:
    /sys/devices/system/cpu/cpufreq/boost
    which can either read "0" (boosting disabled) or "1" (boosting enabled).
    -Reading the file is always supported, even if the processor does not
    -support boosting. In this case the file will be read-only and always
    -reads as "0". Explicitly changing the permissions and writing to that
    -file anyway will return EINVAL.
    +The file is exported only when cpufreq driver supports boosting.
    +Explicitly changing the permissions and writing to that file anyway will
    +return EINVAL.

    On supported CPUs one can write either a "0" or a "1" into this file.
    This will either disable the boost functionality on all cores in the
    -whole system (0) or will allow the hardware to boost at will (1).
    +whole system (0) or will allow the software or hardware to boost at will
    +(1).

    Writing a "1" does not explicitly boost the system, but just allows the
    -CPU (and the firmware) to boost at their discretion. Some implementations
    -take external factors like the chip's temperature into account, so
    -boosting once does not necessarily mean that it will occur every time
    -even using the exact same software setup.
    +CPU to boost at their discretion. Some implementations take external
    +factors like the chip's temperature into account, so boosting once does
    +not necessarily mean that it will occur every time even using the exact
    +same software setup.


    AMD legacy cpb switch
    --
    1.7.10.4


    \
     
     \ /
      Last update: 2013-07-25 19:01    [W:3.141 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site